[R] Bug?

Either something is wrong with my machine or there may be a bugg. I had run
R-1.8.1 two weeks ago. Since yesterday, I am getting this message:<<R for
Windows GUI front-end has encountered a problem and needs to close. We are
sorry for the inconvenience.>> No new software has been installed since I
installed R-1.8.1. Tired to fail getting R-1.8.1 work, I decided to install
R-1.9.0 and got the following message <<Fatal Error. HOMEDRIVE>>. How to
solve either one of these two problems?
Best regards,
Alain